Co-signing a loan for your adult child is not the same as offering a reference. You may be taking on a legal repayment obligation even if no money leaves your account today. Before signing, work out the worst payment you could manage, read the actual agreement, and compare ways to help that do not create an open-ended promise.
This guide develops a publicly posted Korean family-budget scenario for English readers. It is a fictional example, not a real family’s finances or a translation of Korean guarantee law. Loan contracts and guarantor rights differ by place and loan type. Obtain independent local legal and financial advice before signing.
Start with the cost to you, not just the loan amount
Imagine a retired parent with $40,000 in savings. An adult child asks them to back a $30,000 business loan. If the parent ultimately had to pay the $30,000 principal, only $10,000 would remain. Set aside a planned $6,000 home repair and the accessible balance falls to $4,000. This is arithmetic for a teaching example, not a prediction. Interest, fees, collection costs or other contractual obligations could make the outcome worse.
The U.S. Consumer Financial Protection Bureau’s co-signer guide explains the repayment risk using an auto loan. The Federal Trade Commission’s U.S. consumer-credit notice also warns that liability may include more than unpaid principal. These are U.S. examples of the risk, not rules that automatically apply to a business loan or to readers in every country.
Option 1: Help the borrower reduce the amount needed
Best when: the project has costs that can be delayed or scaled down. Do: ask your child to separate equipment, rent, inventory and operating cash. Have them compare a smaller project and financing without your guarantee. Check: the total repayment cost, security required and whether projected cash flow covers payments in a slow month. Limit: a smaller unguaranteed loan can still be unaffordable for the borrower. Taking the loan in your own name merely moves the risk to you.
Option 2: Offer a fixed amount you can afford to lose
Best when: you genuinely want to help but cannot carry the whole debt. Do: first protect your housing, health and emergency cash. Decide on a single amount and an end date, then write down whether it is a gift or a loan. Check: local tax, recordkeeping and repayment requirements before transferring money. Limit: even a small family loan may never come back. Do not call it affordable merely because it is less than the requested guarantee.
Option 3: Help with the numbers instead of cash
Best when: no one has yet tested the borrower’s assumptions. Do: review a cash-flow forecast, existing debts and the first six months of expected bills together. Ask what happens if sales arrive late. If debt is already overdue, use the lender’s or a reputable local debt-advice service. Check: whether the request funds a new activity or just replaces payments on old debt, and verify any upfront fee with the institution itself. Limit: a spreadsheet cannot guarantee a business will succeed.
Option 4: If you are still considering a signature, pause for independent advice
Best when: you have read the alternatives and still wish to assess the contract. Do: obtain the full loan and guarantee documents directly from the lender. Ask an independent professional about the maximum obligation, when it starts, what ends it and whether any property is pledged. Check: how missed payments are reported, whether liability continues after the business changes, and how local law treats this exact form of guarantee. Limit: a private family promise to protect you may not change what you owe the lender.
Three questions to answer before you decide
- If I had to pay under this contract, what would remain for my own essential spending?
- Which terms are written in the lender’s documents, rather than described only in conversation?
- Can I help in a fixed, reviewable way without promising to cover another person’s entire debt?
Saying “I cannot accept an undefined debt” is different from saying “I will not help.” Clear limits can protect both the relationship and your future. For a broader family-budget boundary, see Supporting Parents and Kids Without Losing Your Retirement Plan.
Sources and scope: CFPB and FTC pages linked above, checked October 4, 2026. Their legal examples concern U.S. consumer credit; this article does not export those rules to other jurisdictions or assert that they govern every business loan. The example figures and choices are Money & Why teaching assumptions. This is general education, not individual legal, credit or investment advice.